Electromagnetic clutch control system for vehicles

Abstract

A system for controlling an electromagnetic clutch of an internal combustion engine mounted on a vehicle, which has a magnetizing coil and a transmission. A vehicle speed detecting circuit is provided for producing an output when the vehicle speed exceeds a predetermined speed and another detecting circuit for a vehicle travelling condition is provided for producing an output by signals from a top-gear switch provided in the transmission and from an engine speed switch. A trouble detecting circuit is provided for producing a trouble signal when the output of the speed detecting circuit is not applied in spite of the output of the vehicle travelling condition detecting circuit. A gate device is responsive to the trouble signal for producing an output which is applied to a switching transistor. The transistor is turned on by the output, so that clutch current passes through the magnetizing coil for engaging the circuit.

What is claimed is: 
     
       1. A system for controlling an electromagnetic clutch having a magnetizing coil for coupling said electromagnetic clutch of a vehicle powered by an engine having a transmission with a multi-stage change gears, said magnetizing coil being connected in a circuit to voltage, comprising acceleration detecting means for producing an output signal upon an acceleration action condition of said vehicle,   vehicle speed detecting means for producing an output signal when vehicle speed exceeds a predetermined speed,   vehicle travelling detecting means for producing an output signal when said vehicle is driven at a high speed transmission ratio of said transmission,   a trouble detecting circuit comprising, first gate means responsive to said acceleration detecting means, said vehicle speed detecting means and said vehicle travelling detecting means, and a flip-flop operatively connected to said gate means so as to provide a trouble output signal when said output signal of said vehicle speed detecting means is not applied to said gate means when said output signals of said accelerating detecting means and of vehicle travelling detecting means occur,   second gate means hving gates and being responsive to said trouble output signal, said vehicle speed detecting means, and said acceleration detecting means, said second gate means for producing a first output signal dependent on said trouble output signal, and respectively, for producing a second output signal dependent on said output signal of said vehicle speed detecting means,   switch means provided in the circuit of said magnetizing coil and responsive to the respective said output signals of said second gate means for allowing the current to pass through said magnetizing coil depending on the condition of said switch means,   means for applying pulses to an input of one of the gates in said second gate means, and   said second gate means for producing pulses as said first output signal in response to said trouble output signal, so that said magnetizing coil is intermittently energized so as to partially engage the clutch.   
     
     
       2. The system for controlling an electromagnetic clutch in accordance with claim 1 wherein said switch means is a transistor, which is turned completely on by said second output signal and intermittently on by said first output signal of said second gate means, respectively.   
     
     
       3. The system for controlling an electromagnetic clutch in accordance with claim 1, wherein said vehicle travelling detecting means comprises,   a switch which is closed when the engine speed exceeds a predetermined engine speed, and   a top-gear switch which is closed in a top-gear condition of said transmission, and   said first gate means includes a gating means for producing an output in response to inputs from both said switches.